In remotest 19th-century Wales, teenaged Gwen (Eleanor Worthington-Cox: Maleficent) finds herself trying to keep the family farm running while her father is away at war and her mother (Maxine Peake: Peterloo) succumbs to a mysterious illness.

Gwen is all atmosphere, a dour nightmare akin to a horror movie: first-time feature writer-director William McGregor finds dread and foreboding in the stark gloom of the Welsh landscape, and in the perpetual unease of his young heroine. There’s nothing supernatural here, though. The only monsters are the hardscrabble deprivation Gwen is just barely holding at bay, and the looming menace of unforgiving capitalism: the owners of the local quarry that dominates the area would appear to be behind the torment to which the family is being subjected, their land ripe for mining.

Wales… or Mordor?

But mood and a striking and incisive central performance — Worthington-Cox is previously the youngest ever recipient of an Olivier Award, at age 10, for her starring role in the Matilda musical in the West End — aren’t quite enough to sustain the film, even over its brief under-90-minute runtime. Gwen makes for an impressive calling card for McGregor, however, and I’ll be curious to see what he does with a story that has a bit more meat on its bones.